Drakos-Selinitsa system, Cave system near Agios Dimitrios, Greece

The Drakos-Selinitsa system is an extensive cave network near Agios Dimitrios that stretches through several kilometers of limestone rock. The formation includes multiple levels and numerous branching corridors that create a complex underground maze.

The two caves formed separately along bedding planes and only joined in recent geological time through a near-vertical shaft at the 28 m level, about one kilometre from the Selinitsa entrance. The connection between Katafygi Selinitsas and the underwater Drakos cave was discovered in 2004, giving the system its name. Its development began in the Upper Pleistocene during the last glacial period, between 115,000 and 11,700 years ago, while the Mani peninsula was being steadily uplifted.

The name Selinitsa is the old Slavic name for Agios Nikolaos, while Drakos comes from the spring of the same name about 500 m south of the Selinitsa entrance. The Greek word katafygi means "retreat" or "refuge", the name locals use for the cave. The Greek Speleological Society gave the system its official name after the 2004 connection was found.

The underground space maintains steady conditions throughout the year with moderate temperature and high humidity levels. Visitors should bring waterproof equipment and reliable lighting, as sections of the system feature wet and challenging passages.

The collapse hall of Katafygi Selinitsas measures 252 by 154 metres, the largest of its kind in Greece, and the system's highest point rises 86 metres above its average level of 18 metres. In the cave's inner sediment, fine-grained deposits reach 18.9 metres, matching the Eemian sea level 18 metres above today's and pointing to a marine flood.